Code Enable Criteria

WARNING: This page is about a different car, the 2001 GMC Savana, 2001 Chevrolet RV Cutaway, 2001 Chevrolet Cutaway, and 2001 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.

HO2S voltage is 425-475 millivolts at engine start-up.
Intake Air Temperature (IAT) sensor and Engine Coolant Temperature (ECT) sensor are less than 122°F (50°C), and are within 14°F (8°C) of each other at engine start-up.
Ignition 1 signal is 9-18 volts.
Intrusive tests are not in progress.
Scan tool output controls are not active.
Scan tool is disconnected.
DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0300, P0351, P0401, P0404, P0405, P0440, P0442, P0446, P0452, P0453, P1258, P1404, or P1441 are not set.

DTC sets when HO2S voltage remains within 150 millivolts of start-up voltage for a predetermined amount of time, based on ECT and airflow.